Regulatory Decision Summary for Locametz (gallium [68Ga] gozetotide)

The purpose of the submission was to seek marketing authorization for Locametz (kit for the preparation of gallium (⁶⁸Ga) gozetotide injection), which is a prostate-specific membrane antigen (PSMA) -targeted radiopharmaceutical. PSMA is a type II transmembrane glycoprotein and is overexpressed in prostate cancer, particularly in advanced-stage prostate carcinomas. After evaluation of the submitted data package, Health Canada authorized Locametz for the following indication: Locametz (kit for the preparation of gallium [⁶⁸Ga] gozetotide solution for injection), after radiolabeling with gallium-68, is a radioactive diagnostic agent indicated for positron emission tomography (PET) of prostate-specific membrane antigen (PSMA)-positive lesions in men with prostate cancer:

• with suspected metastasis who are candidates for initial definitive therapy;

• with suspected recurrence based on elevated serum prostate-specific antigen (PSA) level; and

• for identification of patients with progressive metastatic castration-resistant prostate cancer (mCRPC), for whom PSMA-targeted therapy is indicated.

Authorization of Locametz was primarily based on publicly available data in the scientific literature in accordance with the Health Canada guidance document Drug Submissions Relying on Third-Party Data (Literature and Market Experience) and the sponsor conducted study. Two pivotal well-controlled phase 3 studies were provided to support the use of Locametz for detection and localization of PSMA positive prostate cancer. In the first trial, a total of 295 subjects received a single mean dose of 164.2 MBq (4.4 mCi) of gallium (⁶⁸Ga) gozetotide via slow intravenous injection. The primary efficacy endpoints were sensitivity and specificity of PSMA PET for the detection of nodal or distant metastatic disease compared conventional imaging (whole-body bone scan and abdomen and pelvis CT imaging). Each image of the primary efficacy population was read by two blinded independent central readers. The sensitivity and specificity of gallium (⁶⁸Ga) gozetotide PET were 85% and 98% compared to 38% and 91% for conventional imaging, respectively. In second study, a total of 316 subjects with biochemical recurrence were included in the efficacy cohorts. The patient level positive predictive value was 84%. In the sponsor conducted study, a total of 1,003 adult male patients with progressive metastatic castration-resistant prostate cancer received gallium (⁶⁸Ga) gozetotide by intravenous administration and underwent PSMA PET imaging. Improved overall survival was reported in the PSMA-targeted therapy arm.

The safety of Locametz was evaluated in the sponsor’s conducted study. No serious adverse reactions were identified in these studies. The most common grade 1 adverse event was fatigue (1.2%).

Based on the evidence reviewed, the benefit/risk profile is considered acceptable for Locametz under the recommended condition of use.

The recommended radioactive dose of Locametz for PET imaging in adult patients is 1.8 to 2.2 MBq/kg of body weight (0.049 to 0.059 mCi/kg), with a minimum dose of 111 MBq (3 mCi) up to a maximum dose of 259 MBq (7 mCi) as a slow intravenous injection. View the Product Monograph (PM) for details.